International study on <i>Artemia</i>: 19. Hatching data for ten commercial sources of brine shrimp cysts and re-evaluation of the "hatching efficiency" concept

A comparative hatching study has been carried out with reference Artemia cysts as well as cysts from Argentina, Australia, Brazil, Canada, France, Italy, the People' s Republic of China, the Philippines and the USA. Hatching rate, percentage and efficiency vary considerably from one cyst source to another. These hatching criteria are, however, not strainspecific since significant variation is found among cyst batches from the same geographical origin. The limitations of the "hatching efficiency" concept are discussed and a new criterion "hatching output", i.e. the biomass of nauplii expressed in mg dry weight produced per gram cyst product, is proposed for evaluation of the hatching quality of Artemia cyst brands. The hatching quality of reference cysts and cysts from Canada and Argentina can be significantly improved by incubation of the cysts at low salinity. For almost all commercial sources the use of decapsulated cysts results in a significant increase of the hatching output